Hi Carlos,
You have the possibility of reading the manangers as assigned in tcode : PPOMA_CRM , by using the methods in class : CL_CRM_PPM_UM_TOOLKIT.
You can use them in this order:
1. Get the positions in org unit to which user is assigned : GET_POSITION_OF_USER.
2. Get the org unit of each of those positions in step 1. : GET_ORGUNIT_OF_POSITION
3. For each org unit in step 2, get all positions : GET_POSITIONS_OF_ORGUNIT
4. Of all fetched positions , check which is manager position : CHECK_POSITION_FOR_MANAGER
5. Of the position on which 4. return true : GET_USERS_ASSIGNED_TO_POSITION
/Hasan